// https://syzkaller.appspot.com/bug?id=6dcd14a729df98f989c7b76d254226ae67084efd // autogenerated by syzkaller (http://github.com/google/syzkaller) #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include __attribute__((noreturn)) static void doexit(int status) { volatile unsigned i; syscall(__NR_exit_group, status); for (i = 0;; i++) { } } #include #include #include #include #include #include #include const int kFailStatus = 67; const int kRetryStatus = 69; static void fail(const char* msg, ...) { int e = errno; va_list args; va_start(args, msg); vfprintf(stderr, msg, args); va_end(args); fprintf(stderr, " (errno %d)\n", e); doexit((e == ENOMEM || e == EAGAIN) ? kRetryStatus : kFailStatus); } static void use_temporary_dir() { char tmpdir_template[] = "./syzkaller.XXXXXX"; char* tmpdir = mkdtemp(tmpdir_template); if (!tmpdir) fail("failed to mkdtemp"); if (chmod(tmpdir, 0777)) fail("failed to chmod"); if (chdir(tmpdir)) fail("failed to chdir"); } static void vsnprintf_check(char* str, size_t size, const char* format, va_list args) { int rv; rv = vsnprintf(str, size, format, args); if (rv < 0) fail("tun: snprintf failed"); if ((size_t)rv >= size) fail("tun: string '%s...' doesn't fit into buffer", str); } static void snprintf_check(char* str, size_t size, const char* format, ...) { va_list args; va_start(args, format); vsnprintf_check(str, size, format, args); va_end(args); } #define COMMAND_MAX_LEN 128 #define PATH_PREFIX \ "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin " #define PATH_PREFIX_LEN (sizeof(PATH_PREFIX) - 1) static void execute_command(const char* format, ...) { va_list args; char command[PATH_PREFIX_LEN + COMMAND_MAX_LEN]; int rv; va_start(args, format); memcpy(command, PATH_PREFIX, PATH_PREFIX_LEN); vsnprintf_check(command + PATH_PREFIX_LEN, COMMAND_MAX_LEN, format, args); rv = system(command); if (rv != 0) fail("tun: command \"%s\" failed with code %d", &command[0], rv); va_end(args); } static int tunfd = -1; static int tun_frags_enabled; #define SYZ_TUN_MAX_PACKET_SIZE 1000 #define MAX_PIDS 32 #define ADDR_MAX_LEN 32 #define LOCAL_MAC "aa:aa:aa:aa:aa:%02hx" #define REMOTE_MAC "bb:bb:bb:bb:bb:%02hx" #define LOCAL_IPV4 "172.20.%d.170" #define REMOTE_IPV4 "172.20.%d.187" #define LOCAL_IPV6 "fe80::%02hxaa" #define REMOTE_IPV6 "fe80::%02hxbb" #define IFF_NAPI 0x0010 #define IFF_NAPI_FRAGS 0x0020 static void initialize_tun(uint64_t pid) { if (pid >= MAX_PIDS) fail("tun: no more than %d executors", MAX_PIDS); int id = pid; tunfd = open("/dev/net/tun", O_RDWR | O_NONBLOCK); if (tunfd == -1) { printf("tun: can't open /dev/net/tun: please enable CONFIG_TUN=y\n"); printf("otherwise fuzzing or reproducing might not work as intended\n"); return; } char iface[IFNAMSIZ]; snprintf_check(iface, sizeof(iface), "syz%d", id); struct ifreq ifr; memset(&ifr, 0, sizeof(ifr)); strncpy(ifr.ifr_name, iface, IFNAMSIZ); ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_NAPI | IFF_NAPI_FRAGS; if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0) { ifr.ifr_flags = IFF_TAP | IFF_NO_PI; if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0) fail("tun: ioctl(TUNSETIFF) failed"); } if (ioctl(tunfd, TUNGETIFF, (void*)&ifr) < 0) fail("tun: ioctl(TUNGETIFF) failed"); tun_frags_enabled = (ifr.ifr_flags & IFF_NAPI_FRAGS) != 0; char local_mac[ADDR_MAX_LEN]; snprintf_check(local_mac, sizeof(local_mac), LOCAL_MAC, id); char remote_mac[ADDR_MAX_LEN]; snprintf_check(remote_mac, sizeof(remote_mac), REMOTE_MAC, id); char local_ipv4[ADDR_MAX_LEN]; snprintf_check(local_ipv4, sizeof(local_ipv4), LOCAL_IPV4, id); char remote_ipv4[ADDR_MAX_LEN]; snprintf_check(remote_ipv4, sizeof(remote_ipv4), REMOTE_IPV4, id); char local_ipv6[ADDR_MAX_LEN]; snprintf_check(local_ipv6, sizeof(local_ipv6), LOCAL_IPV6, id); char remote_ipv6[ADDR_MAX_LEN]; snprintf_check(remote_ipv6, sizeof(remote_ipv6), REMOTE_IPV6, id); execute_command("sysctl -w net.ipv6.conf.%s.accept_dad=0", iface); execute_command("sysctl -w net.ipv6.conf.%s.router_solicitations=0", iface); execute_command("ip link set dev %s address %s", iface, local_mac); execute_command("ip addr add %s/24 dev %s", local_ipv4, iface); execute_command("ip -6 addr add %s/120 dev %s", local_ipv6, iface); execute_command("ip neigh add %s lladdr %s dev %s nud permanent", remote_ipv4, remote_mac, iface); execute_command("ip -6 neigh add %s lladdr %s dev %s nud permanent", remote_ipv6, remote_mac, iface); execute_command("ip link set dev %s up", iface); } static void setup_tun(uint64_t pid, bool enable_tun) { if (enable_tun) initialize_tun(pid); } static uintptr_t syz_open_dev(uintptr_t a0, uintptr_t a1, uintptr_t a2) { if (a0 == 0xc || a0 == 0xb) { char buf[128]; sprintf(buf, "/dev/%s/%d:%d", a0 == 0xc ? "char" : "block", (uint8_t)a1, (uint8_t)a2); return open(buf, O_RDWR, 0); } else { char buf[1024]; char* hash; strncpy(buf, (char*)a0, sizeof(buf)); buf[sizeof(buf) - 1] = 0; while ((hash = strchr(buf, '#'))) { *hash = '0' + (char)(a1 % 10); a1 /= 10; } return open(buf, a2, 0); } } static void test(); void loop() { while (1) { test(); } } long r[1]; uint64_t procid; void test() { memset(r, -1, sizeof(r)); syscall(__NR_mmap, 0x20000000, 0xfff000, 3, 0x32, -1, 0); memcpy((void*)0x20000000, "/dev/sg#", 9); r[0] = syz_open_dev(0x20000000, 0, 2); *(uint64_t*)0x20001000 = 0; *(uint64_t*)0x20001008 = 6; *(uint16_t*)0x20001010 = 0; *(uint16_t*)0x20001012 = 0; *(uint32_t*)0x20001014 = 0; *(uint64_t*)0x20001018 = 0; *(uint64_t*)0x20001020 = 0; *(uint16_t*)0x20001028 = 0; *(uint16_t*)0x2000102a = 0; *(uint32_t*)0x2000102c = 7; *(uint64_t*)0x20001030 = 0; *(uint64_t*)0x20001038 = 0x2710; *(uint16_t*)0x20001040 = 0; *(uint16_t*)0x20001042 = 0; *(uint32_t*)0x20001044 = 0; *(uint64_t*)0x20001048 = 0; *(uint64_t*)0x20001050 = 0; *(uint16_t*)0x20001058 = 0; *(uint16_t*)0x2000105a = 0; *(uint32_t*)0x2000105c = 0; syscall(__NR_write, r[0], 0x20001000, 0x60); *(uint64_t*)0x20977000 = 0x20e4afea; *(uint64_t*)0x20977008 = 0x16; *(uint64_t*)0x20977010 = 0x20603000; *(uint64_t*)0x20977018 = 0xfa; *(uint64_t*)0x20977020 = 0x2075afb6; *(uint64_t*)0x20977028 = 0x4a; *(uint64_t*)0x20977030 = 0x206b9000; *(uint64_t*)0x20977038 = 0x3d; *(uint64_t*)0x20977040 = 0x2077cfbe; *(uint64_t*)0x20977048 = 0x42; *(uint64_t*)0x20977050 = 0x20c87fbc; *(uint64_t*)0x20977058 = 0x44; *(uint64_t*)0x20977060 = 0x20291f01; *(uint64_t*)0x20977068 = 0xff; syscall(__NR_readv, r[0], 0x20977000, 7); } int main() { char* cwd = get_current_dir_name(); for (procid = 0; procid < 8; procid++) { if (fork() == 0) { for (;;) { if (chdir(cwd)) fail("failed to chdir"); use_temporary_dir(); setup_tun(procid, true); loop(); } } } sleep(1000000); return 0; }